My father used to insert a trumpet mouthpiece into a length of rubber or plastic garden hose and play that. At least I think it was a trumpet mouthpiece - may have been a euphonium or something else larger than a trumpet. It was a long time ago after all! He stopped up the open end of the hose with a finger or thumb and by releasing it partly or fully could vary the note played. He called it a Fartophone. We kids used to go into hysterics.....
Ah, we were easily amused aged about 10.......!
Cheers
JennieG